Influence of physiological and supraphysiological hyperinsulinemia on skin microcirculation in healthy volunteers
Abstract
AIM To examine skin perfusion in dependency on insulinemia in healthy subjects. METHODS: All volunteers were informed in detail about the procedures and signed informed consent.
The protocol of this study was approved by ethical committee. In our study a two-stage hyperinsulinemic euglycaemic clamp was performed, with insulinemia 100 and 250 mIU/mL and glycaemia 5.0 mmol/L (3% standard deviation).
Before the clamp and in steady states, microcirculation was measured by laser-doppler flowmetry and transcutaneous oximetry and energy expenditure was measured by indirect calorimetry. Results (average and standard deviation) were evaluated with paired t-test.
RESULTS: Physiological (50 mIU/L) insulinemia leaded to higher perfusion in both tests- hyperemia after heating to 44 °C– 1848% (984 – 2046) vs 1599% (801 – 1836), P < 0.05, half time of reaching peak perfusion after occlusion release 1.2 s (0.9 – 2.6) vs 4.9 s (1.8 – 11.4), P < 0.05. Supraphysiological (150 mIU/L) insulinemia leaded to even higher perfusion in both tests – hyperemia after heating to 44 °C – 1937% (1177 – 2488) vs 1599% (801 – 1836), P < 0.005, half time to reach peak perfusion after occlusion release 1.0 s (0.7 – 1.1) vs 4.9 s (1.8 – 11.4), P < 0.005.
There occurred a statistically significant increase in tissue oxygenation in both insulinemia. The difference in perfusion and oxygenation between physiological and supraphysiological hyperinsulinemia were not statistically significant.
CONCLUSION: Post occlusive hyperemia test in accordance with heating test showed significantly increasing skin perfusion in the course of artificial hyperinsulinemia. This effect rises non-linearly with increasing insulinemia.
Dependency on the dose was not statistically significant.